For the sake of statistics, it is easier to count monasteries, temples and community buildings. Making a headcount of ordained people is also something quite reliable as long as the government keeps track of them. However, neither monasteries nor ordination define one as belonging to this or that sect, lineage, whatnot.

"There is no such thing as the real mind. Ridding yourself of delusion: that's the real mind."(Sheng-yen: Getting the Buddha Mind, p 73)

According to Wikipedia, a survey conducted in 2012 found that Jodo Shinshu was the most practiced school of Buddhism in Japan with 20% of the overall population identifying as members. Then i wonder what comes in at #2 with the remaining 46% of overall Japanese. This is the supposed source: http://www.worldcat.org/title/japanknow ... /153301537

According to Wikipedia, a survey conducted in 2012 found that Jodo Shinshu was the most practiced school of Buddhism in Japan with 20% of the overall population identifying as members. Then i wonder what comes in at #2 with the remaining 46% of overall Japanese. This is the supposed source: http://www.worldcat.org/title/japanknow ... /153301537

It's interesting the Pew study lists approx. 400 million Buddhists worldwide: Adherent.com lists only approx 376 million. These are terribly misleading figures, and don't account for the majority of Chinese Buddhists simply because some of them may also accommodate Taoism or Confucianism into their beliefs.

The link you gave for Buddhism by country on wiki certainly paints a much larger figure, as does this one at dhammawiki which gives a 'liberal' estimate of roughly 1.5-1.6 Billion Buddhists worldwide. I think that's a conservative estimate personally. Which would mean that there are an equivalent number of Buddhists to Muslims worldwide at least, probably more. That would make Buddhism the number 2 most populous religion worldwide, after Christianity. I hope Buddhism eventually gets the global respect it deserves, as the world's second most populous religious tradition.